PERICENTRIC-INVERSION EVENTS IN KARYOTYPIC DISTINCTION OF BRAZILIAN LIZARDS OF GENUS PHYLLOPEZUS (SQUAMATA, GEKKONIDAE) DETECTED BY CHROMOSOMAL BANDING-PATTERNS

Cytogenetic investigations based on conventional and differential stai ning analysis (C-and replication R-banding and Ag-staining) were carri ed out on eight specimens of Phyllopezus periosus, 17 of P. pollicaris pollicaris, and one of P. pollicaris przewalskii collected from diffe rent localities of Brazil. P. periosus and P. p. pollicaris share the same diploid number of 2n = 40 chromosomes, and their karyotypes are v ery distinctive regarding to the number of biarmed and uniarmed chromo somes. After careful side-by-side comparison of R-banded chromosomes i n both taxa, pronounced homology between, at least, eight pairs was re vealed. The R-banding patterns allowed us to postulate that karyotype differentiation could be due to pericentric inversion events. P. p. pr zewalskii (2n = 38) exhibited a very similar karyotype to that found i n P. p. pollicaris, except for the presence of one metacentric pair, w hich probably resulted from a Robertsonian rearrangement. Single and m ultiple pairs of NOR-bearing chromosomes, showing variation in number and location, were detected among the three forms of Phyllopezus. Simi lar C-banding patterns were found in P. periosus and P. p. pollicaris. Sex chromosomes were not positively identified.